1. Field of the Invention
The present invention relates generally to a seat recliner for vehicles and, more particularly, to a seat recliner for vehicles which improves on the shape of a pair of holders, which are respectively provided on a seat cushion side and a seat back side and contact each other, thus increasing the operability and productivity thereof.
2. Related Art
A seat recliner for vehicles is a device which is provided on a driver seat or a passenger seat. When necessary, an user manipulates the seat recliner to adjust an angle of a seat back with respect to a seat cushion.
A seat recliner for vehicles includes a support bracket mounted on a seat frame in which seat cushion is installed, and a rotating bracket rotatably coupled to the support bracket. A seat back is coupled to the rotating bracket, and the angle between the seat back and a seat cushion can be adjusted by rotating the rotating bracket with respect to the support bracket. The seat recliner also includes a holder assembly that is a device connecting the rotating bracket to the support bracket. Rotation and setting a fixed position of the seat back with respect to the support is achieved by the holder assembly. The holder assembly has a guide holder coupled to the support bracket, and a slide holder coupled to the rotating bracket. The holder assembly further includes a clutch that has lock gears and a cam.
The lock gears and the cam are installed between the rotating bracket and the support bracket. Depending on the rotation of the cam, lock gears expands outwards or shrinks inwards. The rotating bracket has an internal thread in a portion retreated from the surface of the rotating bracket. When the lock gears expands, the lock gears are locked in the internal thread, and further rotation of the rotating bracket is prevented. When the lock gears shrinks inwards, the rotating gears freely rotates in a range preset by the structure of the recliner.
It has been an issue how to safely and securely control the rotation of the rotating bracket that is coupled to the seat back. For the safety of a user, it is important to provide a seat recliner for vehicles that is stable and durable in vibration, impact, and any other external force that could be applied to the seat back. Applicant has proposed a number of seat recliners for vehicles, which were disclosed in Korean Patent Laid-open Publication No. 2003-0092868 (published on Dec. 6, 2003), entitled “recliners for vehicles”, Korean Patent Laid-open Publication No. 2003-0092869 (published on Dec. 6, 2003), entitled “high stiffness recliners for vehicles”, and Korean Patent Laid-open Publication No. 2005-0023110 (published on Mar. 9, 2005), entitled “vehicle seat recliner having improved engagement strength.”
It has been observed that in a poor design of the seat recliner, a machining error could lead to a malfunction of the seat recliner, which could reduce stability of the seat back and could cause an unexpected accident. On the other hand, a complicated design of the seat recliner may increase the security of the seat recliner, but would increase manufacturing cost and reduce efficiency of the manufacturing process. Therefore, it is an object of the present invention to provide a seat recliner that is stable and secure, and at the same time that simplifies the structure and improves the efficiency of the manufacturing process.